add tempname() function to grass.script.core, fix https://trac.osgeo.org/grass/ticket/3615

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@73205 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/script/core.py

@@ -25,6 +25,8 @@ import atexit
 import subprocess
 import shutil
 import codecs
+import string
+import random
 import types as python_types
 
 from .utils import KeyValue, parse_key_val, basename, encode
@@ -822,6 +824,30 @@ def tempdir():
     return tmp
 
 
+def tempname(length, lowercase=False):
+    """Generate a GRASS and SQL compliant random name starting with tmp_
+    followed by a random part of length "length"
+
+    :param int length: length of the random part of the name to generate
+    :param bool lowercase: use only lowercase characters to generate name
+    :returns: String with a random name of length "length" starting with a letter
+    :rtype: str
+
+    :Example:
+
+    >>> tempname(12)
+    'tmp_MxMa1kAS13s9'
+    """
+
+    chars = string.ascii_lowercase + string.digits
+    if not lowercase:
+        chars += string.ascii_uppercase
+    random_part = ''.join(random.choice(chars) for _ in range(length))
+    randomname = 'tmp_' + random_part
+
+    return randomname
+
+
 def _compare_projection(dic):
     """Check if projection has some possibility of duplicate names like
     Universal Transverse Mercator and Universe Transverse Mercator and